Miniature offset press



M. MENDIVIA MINIATURE OFFSET PRESS Filed June 6, 1936 Mahae/ /e/m/a'n'cz,

Nov. 23, i937.

u MN uw @w Patented Nov. 23, 1937 UNITED `STATES `PATENT OFFICE 6 Claims.

My invention relates tor a miniature offset press and it consists inthe constructions,.arrangements and combinations herein described and claimed.

It is an object of the invention tor provide a press of extreme` simplicity yet capable of producing work equal to that of a large press.

It is a further object of the invention to provide a press in which the platen has hingedly connected thereto a plate member for mounting of the lithographie plate, and a work carrying member, each of which is alternately movable into register with the platen to leave and receive impressions from the rubber blanket of the press, the swinging members serving as `the means for obtaining pressure.

It is a still further object of the invention to so construct the lithographie plate carrying member and the work carrying member that they cooperate to produce the required pressures to effect transfer of an impression to the blanket and to the work sheet or card to be printed.

Another object of the invention is the provision of means for accurately registering the lithographic plate and the work carrying member with the platen, and to also provide means for adjusting the rubber blanket of the platen.

Additional objects, advantages and features `of invention will be apparent from the following description considered in conjunction with the accompanying drawing,v wherein- Figure 1 is a top plan view of the press in closed position.

Figure 2 is aside elevation thereof illustrating the lithographie plate carrying member in` position.

Figure 3 is a similar view showing the work carrying member in position to receive an impression.

Figure 4 is a top plan view ofthe press in open position.

Figure 5 is an enlarged side elevation of the platen, illustrating the adjusting feature of the rubber blanket.

Figure 6 is a top plan view thereof.

Figure 7 is a cross section on the ,line 1--1 of Figure 4.

There is illustrated a platen I0 which, in the present instance, is shown as a rectangular block, the respective end portions of which are provided with hinge ears Il. The ears ll are three in number, one adjacent each longitudinal edge of the platen, and one positioned medially of the `longitudinal axis of the block. The ears are each formed with an aperture l2, the axis of which is located slightly above the face I3 of (Cl. 10i- 130) and the ears It also have an aperture adapted to register `with the apertures of the ears l l, and through the aligned apertures a pivot pin l1 is journalled. The ears I l--l Ei, the apertures thereof and the pins il must have rm relation to each other, so as to avoid lateral movements of the members Ul and l5 when moved to operative positions upon the platen. However, in order to more effectively register the members llll5 with the platen, registry guides I8 are positioned at suitable points along the longitudinal edges of the platen, and in use, these guides have sliding, contacting relation with the longitudinal edges of the members |4--l5 when such members are moved into position over the platen.

The outer free ends of the members |4--l5 are slightly tapered and terminate in a trans- 2- versely extended rib i9 which functions as a fulcrum when engaged in the recess 2D of the i upperl members lll-IE, as the case may be, and as will be explained in greater detail hereinafter.

The member l@ carries the printing plate 2l upon its inner face 22, and is held in place by clamp strips 23 which are of course removable, permitting change of printing plates as desired.

The member l5 comprises clips 24 for holding the card or paper 25 up@A which the impression is to be made.

The printing plate 2l and the card 25 are so centered upon their respective members lll- I5 as to register with the rubber blanket 26 of the platen.

The blanket 26 is composed of material now generally used in connection with offset printing and as shown, is yof rectangular form extended transversely of the platen. One end of the blanket 26 is rigidly-secured to the longitudinal edge of the platen by means of a plate 21, while the other end has secured thereto a tension plate 28. The plate 28 is of a length greater than the width of the blank-et, presenting bearing portions 29 projecting beyond opposite sides of the blanr ket. Immediately above each bearing portion 29 there is formed integrally with the platen an apertured threaded lug 30 within which an adjusting screw 3l is engaged. By adjusting the screw 3| the degree of stretch or tension of the blanket may be readily varied.

The printing plate ZI may be formed by any of the well known methods adapted for oiset printing.

The operation The operation will be readily understood from the following description, reference being directed particularly to Figures 2, 3, and 4 of the drawing.

In the open position of the press as shown in Figure 4, the plate ZI will be inked by the use of an inking roller as is customary, and the member I4 then swung into position to lie over and parallel with the platen I El being guided into position by the registry guides I8. Obviously, the plate 2| will rest snugly upon the blanket 26, and the member I 5 is then swung to the position shown in Figure 2. In such position it will be seen that the rib I9 of the member I 4 seats in the recess 20 of the member I5. A downward pressure is now exerted upon the free end of the member I5, causing the plate to leave an inked impression upon the blanket 26. The members I5|4 are then moved to their open positions, and the member I5 is then swung to a. position to lie over and parallel to the platen, presenting the card or sheet 25 directly upon the impression on the blanket. The member I 4 is then swung to the position shown in Figure 3 and pressure exerted upon the free end to complete the printing operation. The parts are then returned to open position, the printed card removed, a new card placed in position and the operation just described repeated. Of course, when the member I5 was swung into printing position, the guides I8 functioned as in the Case of the member I4.

While I have shown and described a preferred form of the invention, this is by way of illustration only, and I consider as my own all such modifications as fairly fall within the scope of the appended claims. Y

I claim:-

1. An offset printing press comprising a platen having a printing member swingably mounted upon one end thereof, a card-carrying member swingably mounted upon the other end of the platen, said members being adap-ted toy be alternately swung into operative position over the platen one above the other, the uppermost member having bearing contact with the other member.

2. An offset printing press comprising a platen having a printing miber swingably mounted upon one end thereof, a card-carrying member swingably mounted upon the other end of the platen, said members being adapted to be alter nately swung into operative position over the platen one above the other, the uppermost member having bearing contact with the free end of the other member.

3. An offset printing press comprising a. platen, a blanket thereon, a printing member hingedly mounted upon one end of the platen, a cardcarrying member similarly mounted upon the other end of the platen, said members being adapted to be alternately swung into operative position over the blanket one above the other, the uppermost member having bearing contact with the free end of the other member.

4. The structure of claim 3 in Which means are provided upon the platen for guidance of said hingedly connected members to insure registry With the blanket.

5. An offset printing press comprising a platen, a blanket thereon, said blanket having one end secured to one side of the platen, adjusting means on the platen and cooperable with the other end of the blanket, a printing member hingedly mounted upon one end of the platen, a card carrying member similarly mounted upon the other end of the platen, said members being adapted to be alternately swung into operative position over the blanket one above the other, a transversely extended recess formed in each of the swinging members, and a rib formed on each of said members adjacent their outer free ends, the rib of the lowermost member having seating engagement within the recess of the uppermost member.

6. A miniature offset press comprising an elongated platen having apertured ears at opposite ends, a plate-carryingr member and a cardcarrying member, each of said members having ears for hinged connection with the ears of respective ends of the platen, means on the platecarrying member for detachably mounting a printing member, means on the card-carrying member for detachably mounting a card to be printed, a blanket on the platen, said swinging members beingadapted to be alternately swung into operative position over the blanket one above the other, guide means on the platen 'cooperable with the sides of the swinging members, a transversely extended recess formed in each of the swinging members, and a rib formed on each of said members adjacent their outer free ends, the rib of the lowermost member having seating engagement within the recess of the uppermost member.

MANUEL MENDIVIA. 

